When do you consider your chicken eggs bad after sitting out?

My family and I have 5 chickens, and one of them just started laying eggs last week. My wife and I have a schedule where she checks the coop in the morning between 7–8 AM (before dropping our son at school and heading to work), and I check when I get home from work at 3 PM.
All week this hen has been laying her egg sometime between those checks. We live in Arizona—temps are starting to drop, but it was still 98° today. Would you guys toss the eggs, or are they still good? I hate to waste them.